Hormone treatment method for inducing estrus synchronization of black goats

Abstract

The invention relates to the technical field of breeding regulation and control of black goats, in particular to a hormone treatment method for inducing estrus synchronization of black goats, which comprises the following steps: placing a CIDR vaginal suppository containing 1.38-1.56 g of progesterone into the vagina of an ewe, and keeping for 12-14 days; 48 hours before the thrombus is removed, intramuscularly injecting a sustained release preparation of 330 IU follicle-stimulating hormone and 30% polyvinylpyrrolidone; when the thrombus is removed, intramuscularly injecting a mixed solution containing 330IU pregnant mare serum gonadotropin and 0.1 mg of cloprostenol; 24 hours after the thrombus is removed, 25 micrograms of luteinizing hormone is intravenously injected to release hormone A3; single-time artificial insemination is performed within 48-56 hours after injection, 0.5 ml of semen is left for each injection, and the number of effective sperms is not less than 1.5 * 10 < 8 >. By precisely regulating and controlling CIDR progesterone and multi-hormone stepped injection, the estrus synchronization rate of a group is larger than or equal to 95%, and the traditional synchronization bottleneck is broken through; insemination parameters are controlled and optimized management is carried out, each fetal live lamb is 2.5-3.0, and the breeding efficiency is improved; treatment is started 45-50 days after delivery, the lambing interval is 210 + / -10 days, and large-scale efficient breeding is assisted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of black goat reproductive regulation, in particular to a hormone treatment method for inducing estrus synchronization of black goats. BACKGROUND

[0002] Black goats have become an important characteristic breeding variety due to their delicious meat quality, strong adaptability and other characteristics, and their breeding scale and industrial benefits have been increasing year by year. However, in the process of large-scale breeding of black goats, the existing estrus synchronization hormone treatment technology still has many technical bottlenecks to be solved, which seriously restricts the improvement of breeding efficiency.

[0003] In the aspect of estrus synchronization regulation, the traditional method mainly relies on a single type of hormone preparation or a simple combination scheme, and the dosage and release characteristics of core hormones such as progesterone are not accurately designed. For example, the commonly used vaginal suppository progesterone has large fluctuations in content (usually randomly selected in the range of 1.0-2.0 grams), and the surface structure is not optimized, resulting in inconsistent progesterone release rate (daily release amount deviation often exceeds 0.2 mg / cm2), which cannot stably maintain the hormone level in the body of the ewe; at the same time, the use of other regulating hormones such as follicle-stimulating hormone (FSH) and pregnant mare serum gonadotropin (PMSG) is mainly instant injection, without forming a sustained-release system, and the injection timing lacks scientific connection, causing hormone action superposition confusion. This directly leads to the estrus synchronization rate of the group generally below 80%, and the estrus time span is as long as 3-5 days, which not only increases the operation difficulty of artificial insemination, but also makes it difficult to realize centralized management, and seriously affects the reproductive efficiency.

[0004] In terms of improving reproductive performance, the existing technology lacks control of key parameters of artificial insemination. The sperm activity is often below 0.6 after thawing, the acrosome integrity rate is less than 70%, and the effective sperm number is difficult to guarantee; the catheter insertion depth is randomly large during insemination, and the sheep body position is not standardized, resulting in low survival and migration efficiency of sperm in the reproductive tract. In addition, the post-treatment nutritional management lacks pertinence, and the demand of ewes for specific nutrients (such as beta-carotene) is not considered, resulting in low pregnancy rate, poor fetal development, and low survival rate of newborn lambs. Finally, the number of live lambs per fetus is maintained at 2.0-2.5, which is far from meeting the production capacity demand of large-scale breeding.

[0005] In terms of reproductive cycle regulation, traditional methods lack scientific design for the timing of estrus initiation in ewes after parturition, relying heavily on experience. This results in significant fluctuations in the timing of the first postpartum estrus (ranging from 30 to 90 days). Furthermore, the timing of each treatment step is loosely controlled; the duration of CIDR vaginal suppository placement and the intervals for hormone injections lack precise standards, leading to lambing intervals generally exceeding 240 days, making it impossible to achieve the highly efficient "three-lambing-in-two-years" reproductive model. This cycle disorder not only reduces the reproductive utilization rate of ewes but also leads to inconsistent breeding batches, hindering intensive management and cost control, and severely impeding the transformation of the black goat industry towards high efficiency and standardization.

[0006] Therefore, in response to the problems of poor estrus synchronization, low reproductive efficiency, and difficulty in cycle regulation in existing technologies, developing a precise and systematic method for estrus synchronization hormone treatment has become a key requirement for promoting the high-quality development of the black goat industry. Summary of the Invention

[0007] Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention achieves a population estrus synchronization rate of ≥95% through precise regulation of CIDR progesterone and multi-hormone stepwise injection, breaking through the traditional synchronicity bottleneck; by controlling insemination parameters and optimizing management, the average number of live lambs is 2.5-3.0, improving reproductive efficiency; treatment is initiated 45-50 days postpartum, with a lambing interval of 210±10 days, facilitating large-scale and efficient breeding.

[0009] Technical solution

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] On the one hand, a hormone treatment method for inducing estrus synchronization in black goats includes the following steps:

[0012] Step 1: Insert CIDR vaginal suppositories containing 1.38 to 1.56 grams of progesterone into the vagina of a black goat ewe and keep them in place for 12 to 14 days.

[0013] Step 2: 48 hours before removing the CIDR vaginal plug, inject the black goat ewe with an intramuscular injection of a sustained-release preparation consisting of 330 IU of follicle-stimulating hormone and 30% polyvinylpyrrolidone.

[0014] Step 3: While removing the CIDR vaginal plug, inject the black goat ewe intramuscularly with a mixed solution containing 330 IU of pregnant mare serum gonadotropin and 0.1 mg of cloprostenol.

[0015] Step 4: 24 hours after removing the CIDR vaginal plug, inject 25 micrograms of luteinizing hormone-releasing hormone A3 intravenously into the black goat ewe.

[0016] Step 5: Within 48 to 56 hours after the injection of luteinizing hormone-releasing hormone A3, perform a single artificial insemination on the black goat ewes. The semen dosage for artificial insemination is 0.5 ml per goat, and the effective sperm count must be no less than 1.5 × 10⁻⁶. 8 indivual.

[0017] Furthermore, in step one, the progesterone release rate of the CIDR vaginal plug is 0.12 mg to 0.15 mg per square centimeter per day, and the surface of the CIDR vaginal plug is provided with 6 to 8 evenly distributed longitudinal grooves, the depth of which is 0.8 mm to 1.2 mm and the width is 2 mm to 3 mm.

[0018] Furthermore, in step two, the molecular weight of polyvinylpyrrolidone is 40,000 Da to 60,000 Da, the mass ratio of follicle-stimulating hormone to polyvinylpyrrolidone is 1:8 to 1:12, and the intramuscular injection is performed using a deep injection method in the lateral neck muscle, with the injection needle inserted at a 60-degree angle to the skin surface.

[0019] Furthermore, the preparation method of the mixed solution of pregnant mare serum gonadotropin and cloprostenol in step three is as follows: after dissolving the lyophilized powder of pregnant mare serum gonadotropin in 0.9% physiological saline, add the cloprostenol stock solution dissolved in anhydrous ethanol. The volume concentration of ethanol in the final mixed solution does not exceed 5%, and it is used immediately after preparation.

[0020] Furthermore, in step four, the luteinizing hormone-releasing hormone A3 injection employs a dedicated timed injection device. This device includes a temperature-sensitive syringe maintaining a temperature between 4 and 8 degrees Celsius, a countdown trigger mechanism with an error not exceeding 3 minutes, and a 23G×1... 1 A 4-inch sterile needle should be used. Before injection, the syringe should be aspirated to confirm that there is no blood backflow.

[0021] Furthermore, in step four, the black goat ewes weigh between 35 kg and 55 kg, have a body condition score of 2.5 to 3.5 before treatment, a cervical diameter of not less than 3 mm, and a serum progesterone level of less than 1 ng / mL.

[0022] Furthermore, in step five, the semen used for artificial insemination has a thawed motility of not less than 0.7, an acrosome integrity rate of not less than 80%, an osmotic pressure of 290 mOsm / kg to 310 mOsm / kg, an insertion depth of 8 cm to 10 cm, and the sheep's body is tilted at a 15-degree angle with the front higher than the back during insemination.

[0023] Furthermore, this method is equipped with a hormone detection system consisting of a portable progesterone rapid tester, a 7.5MHz follicle monitoring ultrasound probe, and an LH peak early warning algorithm based on electrochemical sensor data. The detection limit of the portable progesterone rapid tester is 0.1 nanograms per milliliter.

[0024] Furthermore, within 48 hours after the treatment cycle ends, the black goat ewes are fed a special feed containing 0.3% β-carotene daily, at a rate of 3% to 3.5% of their body weight.

[0025] On the other hand, the application of a hormone treatment method for inducing estrus synchronization in black goats in achieving a two-year, three-production breeding model for black goats specifically includes:

[0026] This treatment method should be initiated on days 45-50 postpartum.

[0027] The lambing interval should be controlled at 210±10 days;

[0028] The estrus synchronization rate of the group is ≥95%;

[0029] The average number of live lambs per litter is 2.5-3.0.

[0030] Beneficial effects

[0031] Compared with known public technologies, the technical solution provided by this invention has the following beneficial effects:

[0032] I. This invention precisely regulates the progesterone content (1.38-1.56 g) and release rate (0.12-0.15 mg / cm² / day) of CIDR vaginal suppositories, combined with a stepwise sequential injection of follicle-stimulating hormone sustained-release preparations (330 IUFSH and PVP compound), a mixed solution of pregnant mare serum gonadotropin and cloprostenol (330 IUMSG + 0.1 mg cloprostenol), and luteinizing hormone-releasing hormone A3 (25 μg LHRH-A3), forming a multi-hormone synergistic regulatory system. This system ensures a stable estrus synchronization rate of ≥95% in the population, overcoming the technical bottleneck of dispersed estrus timing and poor synchronicity (usually ≤80%) in traditional methods. This synergistic regulatory mechanism breaks through the limitations of single hormone treatment and demonstrates a creative application of the laws of estrus regulation.

[0033] II. This invention achieves its goal by strictly controlling key parameters of artificial insemination (semen volume 0.5 ml, effective sperm count ≥ 1.5 × 10⁻⁶). 8(With thawed viability ≥0.7 and acrosome integrity ≥80%), combined with optimized body positioning during insemination (15-degree tilt with the front higher than the back), and feeding with specially treated feed containing 0.3% β-carotene, the average number of live lambs per litter reached 2.5-3.0, a significant improvement over traditional breeding methods (average number of live lambs per litter ≤2.0). This effect was achieved through a systematic design of insemination timing, semen quality, and postpartum nutrition, rather than simply adding up technologies, solving the technical problems of low conception rate and low offspring survival rate after synchronized estrus.

[0034] Third, by precisely setting the treatment start time to 45-50 days postpartum, and combining the timing control of each step (CIDR retention for 12-14 days, hormone injection intervals precisely set to 24 / 48 hours), this invention achieves stable control of the lambing interval at 210±10 days. This breaks through the limitations of traditional breeding, which suffers from long lambing intervals (usually more than 240 days) and low reproductive efficiency due to irregular estrus. By matching hormone treatment with the reproductive cycle, the technical solution is integrated with industry needs, providing a replicable technical path for the large-scale and efficient breeding of black goats. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments thereof. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] The present invention will be further described below with reference to embodiments.

[0037] I. Selection and Pretreatment of Laboratory Animals

[0038] In this embodiment, 80 healthy, disease-free, and reproductively normal Leizhou black goat ewes, aged 2-4 years, were selected and their pedigrees were verified to have no history of inbreeding. Before the experiment, the ewes underwent a 7-day acclimatization period, during which their mental state and feed intake were observed daily, and individuals with abnormal body temperature (deviating from the normal range of 38.5-40.0℃) or reproductive organ inflammation were removed.

[0039] A 5-point body condition scoring system was used to select individuals with a body condition score of 2.5-3.5. Specific criteria included: faintly visible ribs, well-developed back muscles, and a rounded, non-protruding loin angle. The cervix was examined transrectally using a 7.5MHz follicle-monitoring ultrasound probe, and ewes with a cervical os diameter ≥3mm were selected. Serum progesterone levels were measured using a portable rapid progesterone analyzer (detection limit 0.1ng / mL), and individuals with progesterone levels <1ng / mL were strictly screened. The final number of valid individuals included in the experiment was 76.

[0040] II. Reagent Preparation and Equipment Calibration

[0041] (I) Preparation of CIDR vaginal suppositories

[0042] Using medical-grade silicone as a carrier, progesterone (purity ≥99.5%) is uniformly dispersed in the silicone matrix at a dosage of 1.42g / suppository. The suppository is then molded to form a suppository with 7 longitudinal grooves on the surface (groove depth 1.0mm±0.1mm, groove width 2.5mm±0.2mm). In vitro release tests verified that in a simulated vaginal environment at 38℃, the progesterone release rate was 0.13mg / (cm³). 2 ·d), with a continuous release period of ≥14 days.

[0043] (II) Formulation of sustained-release formulations

[0044] Polyvinylpyrrolidone (PVP, pharmaceutical grade) with a molecular weight of 50,000 Da was mixed with follicle-stimulating hormone (FSH, purity ≥95%) at a mass ratio of 1:10. A suspension (concentration 100 IU / mL) was prepared by adding 0.9% physiological saline and refrigerating at 4°C for 24 hours, stirring every 8 hours to ensure sufficient binding of FSH and PVP to form a sustained-release system. High-performance liquid chromatography (HPLC) analysis showed that the FSH encapsulation efficiency was ≥90%, and the in vitro release curves showed a cumulative release rate of ≤30% after 24 hours and ≥70% after 48 hours, meeting the sustained-release requirements.

[0045] (III) Preparation of Mixed Solutions

[0046] Dissolve lyophilized powder of pregnant mare serum gonadotropin (PMSG) (330 IU / vial) completely in 2 mL of 0.9% physiological saline. Separately, take 0.5 mL of cloprostenol stock solution (0.2 mg / mL) and dilute to 1 mL with anhydrous ethanol (analytical grade). Mix the two solutions and bring the volume to 3 mL. At this point, the ethanol concentration is 3.3% (≤5%). Immediately after preparation, dispense into 1 mL sterile syringes and store in the dark at 2-8°C. Use within 30 minutes.

[0047] (iv) Equipment Calibration

[0048] Dedicated timed injection device: calibrated for temperature-sensitive syringes to ensure a constant temperature control accuracy of ±0.5℃ within the 4-8℃ range; the countdown trigger mechanism has undergone multiple tests, with an error ≤2 minutes; 23G×1 1 The 4-inch sterile needles passed the sterility test.

[0049] Semen analysis equipment: Microscope (400× magnification) is calibrated for clarity to ensure sperm motility determination error ≤0.05; Osmometer is calibrated with standard solutions (290mOsm / kg, 310mOsm / kg) with measurement error ≤5mOsm / kg.

[0050] III. Step-by-step operation guidelines

[0051] (I) Insertion of CIDR vaginal suppositories (Step 1)

[0052] Preparation before operation: Preheat CIDR vaginal suppositories in a 37℃ incubator for 30 minutes, and prepare 0.1% benzalkonium chloride solution, sterile gauze, and vaginal speculum (model: animal grade 12).

[0053] Specific procedure: The ewe is restrained in a standing position. An assistant stabilizes the head and hind limbs. The operator wears sterile gloves and rinses the vulva and perianal area with 0.1% benzalkonium chloride solution, then dries with gauze. The vaginal speculum is slowly inserted into the vagina to expose the deep vaginal cavity. Using forceps, the CIDR vaginal suppository is held and pushed along the inner wall of the speculum to the vaginal fornix. When withdrawing the speculum, the suppository tail line is gently pulled to confirm that the suppository is securely fixed. The insertion time is recorded as Day 0, and the suppository is left in place for 13 days (Day 0 to Day 13).

[0054] (II) Injection of sustained-release formulation (Step 2)

[0055] The injection is performed 48 hours before the removal of the CIDR vaginal suppository (i.e., Day 11). The operator uses their left thumb and forefinger to stabilize the muscles on the side of the neck, and holds a 10mL sterile syringe in their right hand. The needle is quickly inserted into the deep muscle layer (2-3cm deep) at a 60° angle to the skin. After aspirating and confirming that no blood is drawn, 3.3mL of the sustained-release preparation (containing 330IUFSH) is slowly injected over 10-15 seconds. After removing the needle, a sterile cotton ball is pressed against the injection site for 30 seconds until no medication seeps out.

[0056] (III) Injection of the mixed solution (Step 3)

[0057] On Day 13 at 8:00 AM, the CIDR vaginal suppository was removed: the operator stabilized the ewe's tail with one hand and gently pulled the suppository's tail thread with the other, slowly removing the suppository completely, and recording the removal time. Immediately after removal, an intramuscular injection was administered on the opposite side of the neck, using 3 mL of the mixed solution prepared in step two (containing 330 IUPMSG + 0.1 mg cloprostenol), injecting it using the same method as in step two, ensuring that all the medication was injected.

[0058] (iv) Injection of luteinizing hormone-releasing hormone A3 (step four)

[0059] 24 hours after the removal of the CIDR vaginal suppository (8:00 AM on Day 14), an intravenous injection is administered using a dedicated timed injection device. The auricular vein is selected; the operator uses their left thumb to press the vein proximal to the heart to fill the vessel, while holding a pre-cooled (4-8℃) syringe with a 23G×1 needle in their right hand. 1 Insert the needle (4 inches) at a 15° angle into the blood vessel. After aspiration shows no blood return, start the countdown trigger mechanism and inject 25 μg of luteinizing hormone-releasing hormone A3 (LHRH-A3) at a uniform rate within 30 seconds. After the injection is completed, use hemostatic forceps to hold a cotton ball and press on the puncture site for 1 minute.

[0060] (V) Artificial Insemination Procedure (Step 5)

[0061] Artificial insemination was performed 50 hours after LHRH-A3 injection (10:00 AM on Day 16):

[0062] Semen preparation: Frozen semen (0.5 mL / vial) was thawed in a 38°C water bath for 30 seconds. Microscopic examination revealed a sperm motility of 0.75, acrosome integrity of 82%, osmolarity of 295 mOsm / kg, and an effective sperm count of 1.8 × 10⁻⁶. 8 indivual.

[0063] Insemination procedure: The operator, wearing a long-arm glove in their left hand, grasps the cervix through the rectum. With their right hand, they insert the insemination catheter (1.2mm outer diameter) along the vaginal wall, passing through the cervix to a depth of 8-10cm. 0.5mL of semen is slowly injected over 15 seconds, followed by a 5-second pause before slowly withdrawing the catheter. During insemination, an adjustable restraint is used to maintain the sheep at a 15° angle (front higher than back), holding this position for 5 minutes before releasing the restraint.

[0064] IV. Supporting Testing and Feeding Management

[0065] (I) Hormone and Follicle Monitoring

[0066] Starting from the 10th day after CIDR vaginal suppository insertion, follicle development is monitored daily at 9:00 AM using an ultrasound probe. The number of follicles with a diameter ≥5mm is recorded. When the follicle diameter reaches 7-8mm, the LH peak warning algorithm is activated (based on an electrochemical sensor that collects a blood sample every 2 hours) to monitor LH concentration changes in real time and ensure that the timing of fertilization is synchronized with the LH peak.

[0067] Serum progesterone levels were measured on the day of CIDR withdrawal and the day of LHRH-A3 injection to ensure that progesterone levels maintained a normal downward trend during the treatment process.

[0068] (II) Post-feeding management

[0069] Within 48 hours after the treatment cycle ends, start feeding a special feed containing 0.3% β-carotene (formula: 60% corn, 20% soybean meal, 15% alfalfa meal, and 5% β-carotene premix). Feed at a rate of 3.2% of the ewe's body weight, twice a day, morning and evening, to ensure that each ewe's daily intake is ≥100mg of β-carotene. Continue feeding for 10 consecutive days.

[0070] V. Application and Implementation of the Two-Year Three-Industry Reproduction Model

[0071] (I) Time Node Control

[0072] This treatment method was initiated on day 47 postpartum: CIDR vaginal suppositories were inserted on day 47 postpartum and removed on day 60 (Day 13); LHRH-A3 was injected on day 61; and artificial insemination was performed on day 63. By precisely controlling the timing of each step, the lambing interval was kept at 210±7 days. Specifically, treatment was initiated on day 47 postpartum after the first lambing. After estrus synchronization, mating, and gestation (150 days), the second lambing occurred 207 days after the first lambing.

[0073] (II) Verification of Group Effects

[0074] Tracking statistics of 76 ewes showed:

[0075] Estrus synchronization determination: 48-56 hours after LHRH-A3 injection, 73 ewes showed signs of estrus by testing rams and observing follicular rupture by ultrasound. The estrus synchronization rate of the group reached 96%.

[0076] Reproductive performance: All 76 ewes in estrus successfully conceived, and 228 lambs survived after delivery, with an average of 3 live lambs per litter, significantly improving reproductive efficiency.

[0077] VI. Key Points of Quality Control

[0078] Reagent Management: All hormone reagents must be stored frozen at -20℃. Thaw them according to the instructions before use to avoid repeated freeze-thaw cycles. PVP must be sealed to prevent moisture absorption and autoclaved at 121℃ for 30 minutes before preparation.

[0079] Operating procedures: Before inserting vaginal suppositories, instruments must be autoclaved (121℃, 30 minutes), and the injection site must be disinfected with 75% alcohol swabs. Artificial insemination catheters are for single use only.

[0080] Emergency treatment: If extravasation of the drug occurs during injection, one-third of the original dose should be injected immediately; for ewes that have not become pregnant 30 days after insemination, serum progesterone levels should be retested, and a second treatment can be initiated if the conditions are met.

[0081] Record tracking: Establish complete individual files, recording in detail the treatment time, reagent batch number, test data and reproductive results for each ewe, and retain them for no less than 3 years.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hormone treatment method for inducing estrus synchronization in black goats, characterized in that, The method includes the following steps: Step 1: Insert CIDR vaginal suppositories containing 1.38 to 1.56 grams of progesterone into the vagina of a black goat ewe and keep them in place for 12 to 14 days. Step 2: 48 hours before removing the CIDR vaginal plug, inject the black goat ewe with an intramuscular injection of a sustained-release preparation consisting of 330 IU of follicle-stimulating hormone and 30% polyvinylpyrrolidone. Step 3: While removing the CIDR vaginal plug, inject the black goat ewe intramuscularly with a mixed solution containing 330 IU of pregnant mare serum gonadotropin and 0.1 mg of cloprostenol. Step 4: 24 hours after removing the CIDR vaginal plug, inject 25 micrograms of luteinizing hormone-releasing hormone A3 intravenously into the black goat ewe. Step 5: Within 48 to 56 hours after the injection of luteinizing hormone-releasing hormone A3, perform a single artificial insemination on the black goat ewes. The semen dosage for artificial insemination is 0.5 ml per goat, and the effective sperm count must be no less than 1.5 × 10⁻⁶. 8 indivual.

2. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, In step one, the progesterone release rate of the CIDR vaginal suppository is 0.12 mg to 0.15 mg per square centimeter per day. The surface of the CIDR vaginal suppository has 6 to 8 evenly distributed longitudinal grooves, the depth of which is 0.8 mm to 1.2 mm and the width is 2 mm to 3 mm.

3. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, In step two, the molecular weight of polyvinylpyrrolidone is 40,000 Da to 60,000 Da, the mass ratio of follicle-stimulating hormone to polyvinylpyrrolidone is 1:8 to 1:12, and the intramuscular injection is performed by deep injection into the neck muscle, with the injection needle inserted at a 60-degree angle to the skin surface.

4. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, The preparation method of the mixed solution of pregnant mare serum gonadotropin and cloprostenol in step three is as follows: after dissolving the lyophilized powder of pregnant mare serum gonadotropin in 0.9% physiological saline, add the cloprostenol stock solution dissolved in anhydrous ethanol. The volume concentration of ethanol in the final mixed solution shall not exceed 5%, and it shall be used immediately after preparation.

5. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, In step four, the luteinizing hormone-releasing hormone A3 injection is performed using a dedicated timed injection device. This device includes a temperature-sensitive syringe that maintains a temperature between 4 and 8 degrees Celsius, a countdown trigger mechanism with an error not exceeding 3 minutes, and a 23G×1... 1 A 4-inch sterile needle should be used. Before injection, the syringe should be aspirated to confirm that there is no blood backflow.

6. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, The black goat ewes in step four weigh between 35 kg and 55 kg, have a body condition score of 2.5 to 3.5 before treatment, a cervical diameter of not less than 3 mm, and a serum progesterone level of less than 1 ng / mL.

7. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, In step five, the semen used for artificial insemination has a thawed motility of not less than 0.7, an acrosome integrity rate of not less than 80%, an osmotic pressure of 290 mOsm / kg to 310 mOsm / kg, and the insertion depth of the insemination catheter is 8 cm to 10 cm. During insemination, the sheep's body is tilted at a 15-degree angle, with the front higher than the back.

8. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, This method is equipped with a hormone detection system consisting of a portable progesterone rapid tester, a 7.5MHz follicle monitoring ultrasound probe, and an LH peak early warning algorithm based on electrochemical sensor data. The detection limit of the portable progesterone rapid tester is 0.1 nanograms per milliliter.

9. The hormone treatment method for inducing estrus synchronization in black goats according to claim 1, characterized in that, Within 48 hours after the treatment cycle ends, feed the black goat ewes a special feed containing 0.3% β-carotene daily, at a rate of 3% to 3.5% of the black goat ewes' body weight.

10. A hormone treatment method for inducing estrus synchronization in black goats, applied to the implementation of a two-year, three-production breeding model for black goats, applicable to the hormone treatment method for inducing estrus synchronization in black goats according to any one of claims 1 to 9, characterized in that, Specifically, it includes: This treatment method should be initiated on days 45-50 postpartum. The lambing interval should be controlled at 210±10 days; The estrus synchronization rate of the group is ≥95%; The average number of live lambs per litter is 2.5-3.0.